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Honda 99 HP New Carb Low range speed issue

gcban

Member
"I need help with my 1987 9.9

"I need help with my 1987 9.9 HP Honda 4-stroke outboard kicker and its low speed rpm problem. Last winter I put a brand new carburetor on this engine. It idles great and runs fine but there is a band from idle to maybe 2000 rpm that it just won’t stay at. It is not a matter of the thrust lock creeping.

I can troll at minimum idle about 1.0 kts, (say 600 rpm) and if I try to add just a little more power to troll say between 1 to 2.4 kts it won’t do it. Accelerates to 2.4 kts (say 2000 rpm) or higher just fine. There is a zone between say 600 and maybe 2000 rpm that it just would stay at. Driving me crazy when I try to troll at 1.5 kts or so. Any suggestions would be appreciated. Thanks!"
 
"Hi Gerry,
Did you replace th


"Hi Gerry,
Did you replace the carburetor to solve this problem or is this a new problem?

You state: "There is a zone between say 600 and maybe 2000 rpm that it just would stay at."

Could you clarify that? Did you mean; "that it just WOULDN"T stay at."?

I work on the small outboards 2000 and newer so I'm not a great source for the older units but it sure sounds like an intermediate carb circuit is either plugged or not venting properly so that makes JUST-IN-TIME's statement probably true unfortunately. The carb is probably wanting a good flush.

Other than that, if you run too much solvent type product like Sea Foam (which I swear by) in your fuel, or if you run some methanol blend or "gasahol" you could have an internal sealing problem in the carb. Sea Foam is great but I've seen people overdose their engines and create problems.

What does she do if you play with the choke while trying to balance the throttle at that medium rpm?"
 
"Thanks for your replies!

J


"Thanks for your replies!

Just-in-Time, you have helped me before and I thank you. I bought a brand new carb last summer due to the old one was just bad, rusted, corroded and would not idle at all, you steered me in that direction and you were right. I have never tried this slow of a troll, engine speed, until now (Out just yesterday 11/14 on Lake Washington) for Cutts and Kokanee. They like a slow troll. All of my previous trolling this and last year was at 2.5 kts plus for King and Silver Salmon so I never noticed it. The engine idles like a dream and I am amazed at how slow it will idle without stalling. I will take carb off and clean.

Jimmy, if the engine is at idle and I want to just add a small amount of power, if I just nudge the throttle a hair, the engine will respond and momentarily go to the new setting no problem. After only about 5 to 10 seconds at that new setting between idle and 2000 rpm lets say, it will either gradually slow down to idle or accelerate to 2000 rpm or so and stay at new setting until the throttle is changed. Throttle remains in same position on tiller handle and has not moved. If power is set at 2000 rpm or higher, or to minimum idle the engine will stay at the rpm all day long.

The only additive I put in my fuel is Sta-bil and I run my boat at least every 4-6 weeks in the winter also and add new fuel as I go to keep it fresh. Outboard is plumbed from main tank thru fuel filter and then also has the filter on the outboard itself. I have not tried the choke during this event. Other then starting the engine when cold, I never have to use the choke. Starts from ice cold on second pull every time and after 1 minute warm up runs like a top (except for my issue above). Thanks again gang. I appreciate your continued help. - Gerry"
 
Garry: If you still have the o

Garry: If you still have the old carb im looking for a plastic choke butter fly valve my engine is a b100 1705933 the number on the carb is o1dcyh7 This engine is a pre 1997 i think-LARRY
 
"Larry,

Wish I could help y


"Larry,

Wish I could help you. When I purchased the new carb, i took the old one to the honda marine parts place in Tacoma to make sure I got the right carburator. I left it there after purchasing the new one since the inside of it was badly rusted in the bowl and jet area. Sorry. G"
 
The motor may be advancing the

The motor may be advancing the timing to cause this problem...use a timing light and keep it on the timing marks and see if the timing advances on its own
 
"This may seem odd, but check

"This may seem odd, but check your thermostat, the motor might be running too cold, causing it to stumble. Check to see if the t-stat is stuck in the open position."
 
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